Since nobody else responded ....
First off, the question might be better asked in the Pronto NG forum. That forum supports the latest models, this forum supports the older ones - 'course maybe you did, I didn't check.
I wish you well. There have been more than a couple "Pronto Killers" come out on the market, but so far.... The latest, soon to be released is the Home Theater Master Mx-3000. On paper, it has features that exceed the newer Prontos, and looks good. You might want to check out it's feature set as well.
Not too many complaints about the Pronto in general. Faster communication (USB as opposed to serial port), more user friendly computer software, an active matrix screen (older color models), and variables and logical operators in programming would be my main suggestions. Oh yeah, a screen that is completely user programmable, or at least the option to completely program or to display only what you want of the fixed user interface.
There were some old "wishlist" threads on the forum. Many of these suggestions were incorporated in the newer versions, but I've found them and the links are below. I haven't reread them, but they may help.
[Link: remotecentral.com], and
[Link: remotecentral.com].
If the project comes to fruition, put me down as a beta tester. ;-)
Jim L