Matt, I'm new here so I don't want to sit and debate audio knowledge all day. I find it hard to believe you've never seen an infinate baffle setup. 10 x Vas is simply a suggested benchmark. It all depends on the speaker. True IB is where Qts = Qtc. I've seen some as low as 4.
Any sub will "work" in IB, it just depends on what you want your response curve to look like. The parameters only dictate the response of the speaker, not how you can install it. If it generates a response you like then it "works" great for your application. You can model responses all day long in WinISD if you want to check out how different speakers react to install types.
Subs that will work well in infinite-baffle setups won't always be labeled as IB drivers. Looking at a sub's specs, look for a high Qts, at least 0.5. Something approaching 0.65-0.7 is better. On the other side of that coin, there are a lot of manufacturers that will claim their subs will work in IB, but this isn't true. At least they won't work well. Look at the Qts. It tells all.