Gainward has a 128MB GF3 Ti200 card available.
Besides that, there is the 128MB SiS315 card available.
Those are the only two consumer graphics cards with 128MB of RAM.
If you want anything else with 128MB of RAM you'll have to look towards ATi's FireGL 4, FireGL 8800, a few 3DLabs WildCat, and GVX models and Evans & SutherLand cards, and nVidia's Quadro 2.
Those are all professional level 3D rendering card made for 3D animation and CAD however and are NOT intended for home users. Besides the Quadro 2, and FireGL8800 the professional level cards will in fact perform quite poorly in gaming.
The SiS315 is also hardly intended for much more then basic gaming uses.
That leaves Gainward's Ti200 w/128MB of RAM as the only real 'gaming' card available with 128MB of RAM.
It's pretty much a useless purchase though as 128MB of RAM is overkill for any modern games. Few games even utilize more then 32MB of RAM even if your running at resolutions like 1600x1200x32bpp.
Unless this guy intends to run all his games at 1600x1200x32bpp w/4X FSAA enabled then I can't realistically seeing him gaining much from having more RAM on a card.... even the best cards available would choke and die trying to run with 4X FSAA at 1600x1200x32bpp anyway.
The highest performance gaming cards presently available are ATi's Radeon 8500, and nVidia's GeForce3 Ti500.... both of which are only available with 64MB RAM.