It sounds like you and I are at about the same stage in our router development! I'm in the process of building a table as well. I did build one years ago, but it lacked a plate and I soon learned it was inadequate for my needs. I bought one from Sears...big mistake! The aluminum top, insert rings, and fence were all disasters.
That brings me to the now...building another table. I spent a lot of time pondering the plate situation. Early on I rejected those with the fixed hole diameter like yours. I finally, this morning in fact, ordered one from MLCS. Their phenolic plate is on sale for $34.95 right now and it comes with two rings (one inside the other), which effectively gives you three hole sizes. The smallest opening is also supposed to take Porter Cable style guide bushings. My biggest debate was whether I should get the phenolic plate or the aluminum, which was nearly twice the price. After hanging out here and noting how many here have built their own plates out of phenolic, I figured it would probably outlast me, so that's the route I took.
I guess I didn't really answer your question, but I can commiserate with you none the less. The MLCS plate is pretty affordable if you find that you do have to get a different one.