Hi all, I am new to VOIP & TrixBox but comfortable with Linux and simple telephony. (I can punch a T1 down on 66 block

) A friend gave me an old AT&T Merlin 410 keyset with 6 extensions to play with.
It uses PSTN trunks, and digital (ha!) phones. However handy it is it doesn't have caller id or voicemail, what I was thinking was the following:
1. FXO for our main PSTN line with failover incase network or power dies
2. 1 FXS for each trunk on the keyset (4) (?)
3. TrixBox to route inbound calls based on callerid. Friends & Family on line one, work on line two etc. Jerks and telemarketers get sent to evil recursive menu options.
4. Finally set up a voip account to dial out in the rare event the main line is tied up.
To that end I was thinking a Linksys SPA-3102 would be the ticket and maybe a Linksys PAP2T for a few extra trunks.
Mind you this is really just to play with so I don't need to blow a million bucks. (My budget is about $150.)
Any thoughts?