If you want something big and hefty for the job, the new Juliano is a bit too new for your use, but you could justify a prototype (or at least build an Omni config based on it). 24 Streak SRMs per turn is nothing to sneeze at.
If you don't mind doing a bit of customization, the AXM-2N Axeman makes a fine SRM boat if you replace the LRM-15s with four SRM-6s- even have a bit of spare room for a couple of heat sinks. So a large pulse laser, four SRM-6, three medium lasers, and- if you prefer over the lasers- follow up with a smack from an axe. It runs a bit warm, no doubt, and could use a bit more work (I like to replace the LPL with a standard PPC, then move it to the right arm and the mediums to the left), but it's a remarkably handy little monster.
Oh- and if you are okay with a hovercraft here and there, the Plainsman is simply bliss. Two SRM-6 in a turret, and an SRM-2 that one will enjoy putting smoke or inferno rounds in for a little extra fun, and on a fast, surprisingly tough little frame.