This has been discussed a lot.

Daniel, have you thought about a "Remote FAQ".

My take on it is, that for a few years some "Elite" products used high frequency IR.
The Pronto can not learn that high freq.

But supposedly these same models have alternate low frequency IR codes it will listen to and may be found in a cheap One-For-ALL or similar remote.

Rumor also has it that the Pronto sister remote RC-5000 will be able to do High Freq IR.

All this was taken from "Remote Central" so look back for more details.