Re: IDX Solution
Matt - you will find that almost all third party vendors are inflexible (They make their $ on volume and residuals (And beware the hidden fees, something that is $20 a month to start can wrack up $400 in usage fees pretty quickly)
I don't think you will get everything you are looking for on your budget, but the trick is to find the canned solution that (Out of the box) fits your needs. Most IDX vendors should have a trial and or a demo you can use.
Starting LEC 7 soon but it won't be called LEC 7 - LEC 2012 coming soon!