noneof these remotes have a feature for extended transmition, but sometimes (used it with Prontos a lot) you cna build a macro that sends the code over and over again. On the other hand onmy NEC projector there is a menu setting where you can switch from long press to confirmation page.
as for
Which remote would have the feature to control the length of the IR transmission?
I think the MX-3000 has it (not sure) but not many of them
