I am slowly getting my Toshiba M400 working with Snow Leopard 10.6.2. I installed iPortable_Snow_X86 with the Chocolate kernel and am incrementally installing the .kext files you supplied to me (thanks greatly to you for being so generous). I haven't had any kernel panics except for firewire .kext problems so I removed them. So far I have the display working with Quartz, etc., and as a tablet with screen rotation. It will work with an external LCD but only internal or external, not both. I am also using an external Belkin USB wireless with drivers from Ralink's website. I will post further developments here as I succeed with them. Did you ever update to 10.6.3?
You should probably use a slightly newer distro. I don't remember how I set up Leopard, but I have sound working on Snow Leopard and accelerated display (had to use old framebuffer drivers but it works great).
The WiFi never worked for me, but my M400 came with an unsupported WiFi card anyhow, so I just bought a small USB wireless dongle that works quite well using Ralink drivers.