I'll go for one for each team with their age
Cowboys- Matt Bowen 33
Souths- Nathan merritt 32
Titans- Preston Campbell 38
Roosters- Anthony Minichiello 35
Warriors- Lance Hohaia 32
Sharks- David Peachey 41
Eels- Luke Burt 34
Knights- Timana Tahu 35
Storm- brett finch 34 (not many options for storm)
Manly- steve menzies 42 ( not many options for manly)
Tigers- todd payten 36 ( ball playing forward)
Panthers- Craig Gower 37 ( not many options for panthers)
Raiders- Alan tongue 35 ( not many options for the Raiders)
Bulldogs- Willie Mason 35 ( assuming he isn't going around again for manly, be a good way to say goodbye with the club that gave him his big break)
Broncos- Jharal Yow Yeh 25 (depends on his injury, but if he could manage a weekend out of it it'd be a great way to say goodbye to a players who's career was taken way to short)
Dragons- Anthony Mundine 40 ( would still be fit due to the boxing, was always a naturally gifted player. Whether you love him or hate him, or if he succeeded or failed, he'd bring in a lot of interest)
So freddie was 42 when he went to the 9s so that was my age limit. Of the guys in their 40s Peachey is still popping up in bush leagues, Beaver only retired in 2013 and Mundine is in good shape from boxing. Most players are fan favourites for their clubs, i mainly tried to stick to attacking backs but even in 9s their is still room for a hard working forward like tongue