Maybe try looking for a used one on ebay, Craigslist, audiogon, etc. or move the L/R speakers to stereo duty and buy a new front trio. That's what I would do. Unless the front L/R are that good, then keep searching for a used one to come up for sale. What are they, anyway?
Is there a noticeable difference between the ec25 and ec35? Should I wait for a ec35 or just go right ahead with the ec25 since I know I can get them.
There is a huge difference b/w the 25 and 35. The EC35 has larger mid bass drivers and a midrange. It sounds so much better than the EC25. I bought 2 EC35's a few yrs ago and I love them so much. I gave the EC25 to a relative after I bought and listened to the EC35. That's the reason I bought 2 EC35's before they completely disappeared.
In the meantime should I buy either the e30's or e50's? Do you have a sub recommendation? I have a friend that has the l8400p, but i'm not sure if I should buy a certain series or if it doesn't matter.
If you can get the E50's, you can use one of the E50's as the center speaker, which would be the best match for your front E100's. The subwoofer does not need to be from the same series, you can get any sub you like.