Any drive pedal with more gain and distortion than the TS9 should give you a wider array of sounds. Maybe a DF7? Hehehe. I use a TS9-DS1 cascade myself, and it pretty much covers any drive requirement. But i'm thinking a TS9-TS9-Delay chain might be better for my needs.
Dude, consider na lang having your TS9 modded. That chip inside of it is capable of so much more gain. To give you a number, it's capable of a gain factor of 200,000 per gain stage, and there's 2 of them ! In laymans terms, if I put in 1 volt in the input, it is capable of spitting it back out (theoretically lang ha) at 200,000 volts ! Of course this is not done in real life, first, you'll need 200,000 volts of input powering voltage, second, the OP-AMP chip has to be able to withstand that kinda voltage (and none of them can) and third, it will result in massive amounts of feedback if you put that kinda gain on.
So, it's just the design of it that clamps down the gain to an "over-drivish" range. In theory, and yes I can prove it, you can even modify a TS9/TS7 to rival the grit and angst of a Metal Zone. Unheard of ba ? But that's the truth.
Knowing what I know about it, it's a waste of money to chain 2 TS9's just to get gain. Of course, that's just me and of course, some tweaking is required.
BAMF