As known, an increasing number of new items is offered by both, Märklin and TRIX, with different road numbers.
Especially with cars, TRIX models offer an excellent opportunity to complement their corresponding Märklin models/trains.
Following you'll find a first list of those (no claim for 100% accuracy or completeness). Also listed are models which are offered on both product lines, but having same road numbers.
M39020: DRG BR18 321 - SDS, mfx, full sound (T22180 same roadnumber)
M39025: DRG BR18 327 - SDS, mfx, no sound (T22181 same roadnumber)
M41928 DRG Rheingold car set (T23430 same roadnumbers)
SA4ü-28: 20506, SA4ük-28: 20505, SB4ü-28: 24501, SB4ük-28: 24502, SPwü-28: 90201
M42755: Sleeper: 665A, 1961A; Baggage: 1204, 1206; Dining: 1733D
M42760: Sleeper: 1959A, 1983A
M39410: DB E41 208 - SDS, mfx, full sound (T22140 same roadnumber)
T22142: DB E41 219
M43800: DB B4nzb-59 - 43058Stg(*) (T23407: 41237Stg (*))
M43810: DB AB4nb-59 - 31229Stg (T23406: 32522Stg)
M43820: DB BD4nf-59 - 96426Stg (T23405: 96385Stg)
(*) different road number on katalog picture
M39411: DB-AG 141 061-2 - SDS, mfx, full sound (T22141 same roadnumber)
T22143: DB-AG 141 074-5
M43801: DB-AG B4rz 450.3 - 50 80 22 35966-7 (T23433: 50 80 22 35978-2)
M43811: DB-AG AB4n 417.1 - 50 80 30 35112-7 (T23432: 50 80 31 54286-5)
M43830: DB-AG Bnrdzf 463 - 50 80 82 34042-5 (T23431: Bndf 478 - 50 80 82 53911-7)
M39189: DB 210 001-4 - SDS, mfx, full sound (T22222: 210 002-2)
M39300: DB 230 001-0 - SDS, mfx, full sound
M43958: DB "Bavaria" TEE car set (T23427)
Avümz 111 - 61 80 19 70015-1 (T23427: Avmz 111 - 61 80 19 80025-8)
Apümh 121 - 61 80 18 80105-9 (T23427: Apmz 121 - 61 80 18 70004-6)
ARDümz 106 - 61 80 84 70201-7 (T23427: ARDmz 106 - 61 80 84 70202-5)
M39421: SBB Re4/4-I 10023 - HLA, simple fx (T22353 same roadnumber)
M36331: SBB Ee3/3 16367 - DC, mfx, no sound (T22335 same roadnumber)
M43361: SBB A - 50 85 18 33037-0 (T23340: 50 85 18 33021-4)
M43371: SBB B - 50 85 29 35595-4 (T23341: 50 85 29 35669-7)
M43381: SBB B - 50 85 20 33044-2 (T23342: 50 85 20 33023-6)
M43391: SBB WR - 50 85 88 33103-5 (T23343: 50 85 88 33100-1)
M43401: SBB D - 50 85 92 33502-2 (T23343: 50 85 92 33521-1)
M43430: SBB ABt - 50 85 38 33932-8 (T23340: 50 85 38 33933-6)
And here just for completion some road numbers for specific models.
M00770/1: DB AB3yg-54 - 37361Stg, B3yg-54 - 85950Stg
M00770/2: DB B3yg-54 - 86626Stg, B3yg-54 - 86627Stg
M00770/3: DB B3yg-54 - 86271Stg, BD3yg-54 - 99481Stg
M26534: DB 38 1885 - DC, mfx, full sound
M26544: SBB Re484 016-1 - DC, simple fx
M29010: DB 01 1060 - SDS, mfx full sound (cars: A4üm-63 12059Esn, B4üm-63 19501Esn, 19505Esn)
M29130: DB-AG Railion 185 156-7 - DC, simple fx
M29151: DB 151 023-9 - HLA, mfx, no full sound
M29160: DB 81 008 - DC, simple fx
M29476: DB 218 424-0 - HLA, simple fx
M29481: SBB Re 4/4-II 374-0 - HLA, simple fx (German/Swiss pantos)
M29532: DB 86 130 - HLA, simple fx (with Telex)
M36081: DB V80 005 - DC, simple fx (T22075 same roadumber)
M36240: DB 24 016 - DC, simple fx
M36420: DB-AG 232 658-5 - DC, simple fx (T22070 same roadnumber)
M36421: DR 132 529-7 - DC, simple fx (T22071 same roadnumber)
M36792: ÖBB 2016 25-5 - DC, simple fx (T22074 same roadnumber)
M36826: DB-AG 323 541-3 - DC, mfx, no sound (T22139 same roadnumber)
M36838: Veolia 185 CL002 - DC, simple fx (T22076 same roadnumber)
M37033: SNCB Serie 64 - roadnumber not yet confirmed, DC, mfx, full sound (T22359 same model)
M37054: DRG 59 004 - DC, mfx, full sound (Bellingrodt Edition)
M37122: NS/ACTS 1251 - HLA, mfx, no full sound (T22149 same roadnumber)
M37238: SNCB Serie 25.5 2551 - roadnumber not yet confirmed, DC, mfx, full sound (T22357 same model)
M37253: DB Kittel Dt8 - DC, mfx, no sound (T22033 same road number), BD Karlsruhe, Bhf Freiburg
M37421: NS ELD4 4221 "Koploper" - DC, mfx, no full sound (T22355 same roadnumber)
M37539: DB-AG 120 123-5 - HLA, mfx, no full sound
M37635: NS/ACTS MaK1206 7101 - DC, mfx, no sound
M37636: CFL MaK1206 1502 - DC, mfx, no sound (T22360 same roadnumber)
M37763: DB-AG VT 628-2 - 628 350-1, 928 350-8, HLA, mfx, no sound
M37730: DB-AG 648.2 Lint - ABpd 648 752-6, Bpd 648 252-5 - DC, mfx, full sound (T22211 roadnumber yet tbd)
M37735: DB-AG 648.2 Lint - ABpd 648 759-9, Bpd 648 259-0, DC, mfx, no sound
M37670: DSB My1145 (Ep.V), My1103 (Ep.III) - HLA, mfx, full sound
M37940: SJ T44 376 - roadnumber not yet confirmed, delivery planned for 2009, SDS, mfx, no sound (T22352 same model)
M37848: DB 50 1035 - HLA, mfx, full sound
M37887: SNCF 150 X 1518 - HLA, mfx, full sound, (T22147 same roadnumber)
M37966: DRG 96 006 - HLA, mfx, full sound
M39011: DRG 01 128 - SDS, mfx, full sound (T22028 same roadnumber)
M39183: DB 218 26-6 - SDS, mfx, full sound (T22221 same roadnumber)
M39343: DB-AG 152 005-5 - SDS, mfx, no full sound ("Patricia")
M39501: DB 150 084-2 - SDS, mfx, no full sound (T22151 same roadnumber)
M39640: DB 64 250 - SDS, mfx, full sound
M39645: DB 64 278 - SDS, mfx, no sound
M39641: ÖBB Rh 64 31´- SDS, mfx, full sound
M39836: ÖBB Rh 1216 236-6 - SDS, mfx, full sound (delivery planned for 2009)
M39892: Siemens/ÖBB ES 64 F4-006 - SDS, mfx, no full sound
M39893: SBB Re 474 014-8 - SDS, mfx, no full sound
M39894: SJ Hector-Rail 441 002-3 - SDS, mfx, no full sound
M39191: DB 119 012-3 - SDS, mfx, no full sound
T22348: ÖBB E18 42
T22606: DB 119 002-4
T22605: DRG E19 01
T22148: SBB Re 4/4-II 11250 TEE - (HLA, NEM)
T22036: SJ G 1414 - (M37555 same roadnumber, new item 2007)
Note: TRIX models are usually equipped with mtc-plug or 8-pin NEM socket. The following models are equipped with DCC/SX decoder and(optional) sound: T22053, 22070, 22071, 22074, 22076, 22139, 22140, 22141, 22147, 22149, 22180, 22181, 22203, 22213, 22214, 22222, 22307, 22352
Model railroading is fun!

PS: Added some more models, motor and decoder type to the list (last updated 2008-11-22).