Just when you think you've found the website or store you can stick with... you know, stuff happens.
I've been happy with xpmedical for some time. In fact, I still am but Tena has everything on backorder and I'm not a fan of most of the rest of their plastic backed diapers. So back to searching I went.
After spending a good while, I stumbled on vitalitymedical.com. They have a pretty good selection of diapers from Tena, Molicare, Tranquility and many more. The prices are all reasonable to down right cheaper than expected. There are actual people working the phones if you give them a call too.
While checking their selection, I found that they carry a line of Molicare I had only seen one other place, at a much better price. The Molicare comfort plus. It is a very thin diaper, with breathable side panels but plastic backsheet. While it is thin, and inexpensive ($58 for a case of 90) they hold up very well. I've given them 2-3 full wettings without leaks. I wouldn't recommend them for 8+ hours use, or overnight, but for a day time diaper they are really good. Even more so if you're looking for a plastic diaper.