Most DVD movie playing problems are caused by your system, and not the drive, especially at high resolutions. When I first bought my DVD-ROM drive, I couldn't play DVDs at higher resolutions like 1280x1024, 1600x1200 without it constantly pausing and skipping. I talked to a buddy of mine at the computer shop, and we determined that the problem was being caused by my old TNT2 32 MB video card. I bought a new TI4600 and the problem disappeared. Mainly the point here is that you really don't need a huge buffer for playing DVD drives, and I really don't know of many drives that have a read buffer in the sizes you are wanting, its just not necessary.
My Desktop: <A HREF="http://Mr5oh.tripod.com/pc.html" target="_new">http://Mr5oh.tripod.com/pc.html</A>