An update: I purchased two 32GB SLIM SSDs from dvnation—shipped quickly and arrived as expected—and installed them in two X505s. Thanks very much for the step-by-step X505 disassembly instructions on this site; they were a lifesaver.
Hints:
I installed the hard drive upside down the first time (no indication which is right-side up, but no damage as a result either). Make sure the side with fewer chips is facing up.
When disassembling, keep the unit closed. Replace the drive. Reassemble completely, including the battery. For some reason, at least on my unit, there was a lot of extra tension on the hinge, so if it isn’t put back together as designed before opening, the hinge can (and did) easily snap.
The SLIM SSD is actually smaller than the 20GB hard drive. I peeled off the rubber side-protectors from the hard drive, attached them as best I could to the SSD, inserted the SSD and then added some filler material on the sides to make sure the SSD didn’t move too much. I’m a little concerned about my choice of filler material (paper-like material) because of all the heat the CPU generates. Anyone think that’s a problem?
Summary
The SSD’s work like a charm. Darn fast.
Hope this helps!