I think I found a 256mb sodimm that may work with the i-opener based on the specifications that Programmer was nice enough to provide info for (thanks!) - it's pretty pricey compared to other sodimms, but it looks like it may work, and may be worth it to some people. I'm probably going to order one next week to try it out from www.memory.com. I'll keep you posted.
--- I sent him Programmer's post:
"the configuration of the sodimm is actually rather unimportant to us, and it is the sdram chips ON the sodimm that are our problem. The sodimm pictured looks to have 4 chips on the side that we can see. If that is all the chips it has, it is using 512Mbit sdrams, which will not work for us. If it has another 4 chips on the back, then it is using 256Mbit sdrams, which will also not work. Our only hope for 256MB on the IO is to use a sodimm that has 16 128Mbit chips.
is one such device, if you look at the datasheet you can see that it uses shrink-tsop sdrams, and fits 16 of them 8 per side on a regularly sized sodimm.. samsung doesn't list any 512MB sodimms, so obviously they don't have one with 32 shrink tsops somehow stuck to a board..."
--- and here's the reply that I got:
We do offer a chip that matches these specifications perfectly.
Description: 144 Pin SDRAM PC100 DIMM 3.3v 256MB DIMM (32Mx64 DIMM /16Mx4/CL3) (using 16 chips, 128MBit Technology, very low profile)
Part # A32MSS64V8L
Alpha Memory, Inc."