I have 3 partitions on my 256gb system drive (SSD) in my MP 6,1 each with a different variant of Mac OS and PT, I don't store audio/video or record to these partitions, they are purely system drives... never had any issues.
I also run a 256gb SSD in mp old MP 3,1 with 2 partitions, one for the mundane office type stuff and the other as my studio space, on the studio partition I run Logic & PT, all the Logic sample libraries and VI's are stored and installed on the studio system partition and any audio or video is stored/recorded to a seperate HDD spinner... this setup has been working perfectly for years.
As for Trim support, it's pretty much ONLY available with the HORRIBLY over priced Apple supplied SSD's (there are 3rd party utilities available) and is pretty much a non issue as long as you are not in the habit of constantly moving and erasing data on the SSD (remember, I'm only using them as system drives).
So, I say partition away
