..........spending your hard earnt cash on that West Marine RIB. Why ? Well in the first instance it's expensive for what it is, however, anything brand new always is. Next, it's only rated for a 10hp which, although enough for a chap your age I feel sure that once you really get bitten by the RIB Bug you'd feel restricted by 10hp performance and want to jump to 15hp especially when one of your pals passes you and leaves you in his wake.
Therefore, if I were you I'd search for a 2nd hand RIB with a minimum length of 3.80 mtrs which would be capable, in most cases of taking upto a 40hp whilst still delivering sound performance with a 15hp on the tail. In this way, once you feel ribbing is for you there's the option to upgrade your engine. Furthermore, it's always safer and more fun to boat with a pal either in a seperate boat or by your side (even better with a girl) therefore, a 380 has the room and of course some added stability and performance in differing sea conditions.
Where to look... well, if you were in the U.K we'd be laughing however, we're not so why not search through the classifieed adverts in your local paper, visit the marina and search the notice boards in yacht clubs, chandlers etc and one tip that has always worked for me, put your own advert together "Wanted" with a few well chossen words and stick it wherever you see "For Sale" adverts. Someone is bound to see it and may just have what your looking for whilst not exactly realising they wanted to sell it - if you get my drift.
Furthermore, please don't dismiss a SIB as they're just as much fun and just as safe for inshore pottering from here to there. If Keith Heart reads this I'm sure he'd vouch for this fact. SIBs are also a lot cheaper, easier to come by and whilst I appreciate you say portability is not a factor, the lightness of such craft has real advantages, especially if I may be so bold, for a chap of your age.
I hope the above is of assistance ! Good luck with your search - keep us informed.
By the way, this site may be of assistance in bench marking whats about. www.boatsandoutboards.com