My delema is that I outgrew my 507cmx. I need more inputs, but I cannot find that key digital card anymore so I need to upgrade.

I bought the 507cmx in January of 07 for 2300 shipped.

A local mom and pop tv store is willing to "buy it back" the 507cmx for $1500

And sell me a New 6070 for an additional $2600, so the full price is $4100

Is this worth it? Should I be looking for something else?

The upside is that I do not have to mess with selling my old one.

Any input or alternate scenarios welcomed.

NO! That's a terrible price for a 6070. You can get it close to that without the "buy back". I'd ask them what they would sell you the 6010 for, this year's Pioneer 60" panel. Now, that would be a decisive step up.