Hey guys - thanks for all yalls input. we take pretty much everything posted here to heart, and this is certainly no exception.
The fact of the matter is that the 720 is reaching the end of it's service life. Your units are still going to work just as well on Jan 1 as they are now. You will still get updates, and to be hoenst with normal use you're probably not going to be affected unless it needs to be repaired - just like the 700 and 520.
The 740 series is in the early service life now, and will be around for a while. I don't see that changing.
With regards to what I guess we could call a 760 - We have had a few discussions about it in passing here at the office, but we have so much going on that even thinking about what's after the 740 isn't even on our radar for at least another year.