If you're looking for a ray specialist, you could try the Arcane Assassin from Crimson Contracts. You have to be evil, though, so it might not be up your alley. I don't know what to recommend for a summoner.
Summoning: Alienist from 3.0 Tome and Blood or 3.5 Complete Arcane
Mixed with a Conjurer (Specialist Wizard).
The 3.5 version has been neutered slightly compared to the 3.0 but they were a little overpowered.
They are a little bit out there but hey... they're fun. You can read about one in my Story Hour - devoted to Lucifus Cray who is an Alienist - or if you really want to read about an Alienist, check out Sepulchrave's story hour. Mostin is THE alienist for me!
Eldritch Knight is a pretty good PrC for a ray specialist. It doesn't have a lot of bells and whistles, but good BAB and +9 spellcaster levels pretty much assures that you'll hit what you're aiming for, and what you're throwing is nasty.