This message may seem a bit condescending but please don't take it as that. I have no clue as to your ability to play guitar, or your experience in dialing in amps, however, I do notice that you are making a fairly common mistake when it comes to your expectations of "gain". This is evident in your assertion that a tsl does not have enough gain for your taste.
One thing I found in my quest for gain (every guitar player goes through it) is that gain isn't exactly what you think it is. Remember, most of the recordings you hear are heavily studio processed. They use all kinds of gear to get the sound to the shape that they want. They have processors in front of the gain stages of their amps that provide a hotter signal into the pre-amp. They are also not recording at gigging levels.
When these bands go on the road, things sound different. They don't always use the same equipment etc. This is why live concerts sound significantly different than most studio stuff.
What you really need to do is change your quest. Move from a quest for gain, to a quest for tone. Don't try and reproduce what you hear on CD's etc. Try and create sounds from your gear that capture the atmosphere of what you are copying.
VERY few amplifiers sound good with the gain maxed. My son played like that all the time and it made me cringe. Maxing out the gain has 2 major bad influences on your sound.
1) Makes it sound thin, and when you play with others, you will NOT cut through the mix
2) Makes it VERY noisy. When you play with others your amp will be howling all the time because the volume level you have to run to cut through will cause your rig to feedback
Not to mention it will wear out your pre-amp tubes very quickly. In fact, in most mesa boogie manuals it warns against maxing the gain. In fact, as far as "high gain" amps go, MESA is not the be-all-end-all. In fact, they are pretty much middle of the road.
Take Zakk for example. Live, he uses hot rodded marshalls for his sound. He's got them setup for his rhythm sound. When he wants his lead tone, he stomps on a boss SD-1 overdrive. In an interview I read once, he said "when you step on that OD, you better be playing" or something like that. This is because his rig will make everyone's ears melt if it starts to feedback, even in a stadium.
Slash is very similar. Heavier bands do the same thing, but typically have rigs setup for their sound. Pre-amps before their actual amps (very generically speaking that is).
So, basically, what I am trying to say is, do not purchase an amp with your main purchasing factor being the amount of gain that you are after. Find an amp that you fall in love with the tone, then start shaping your sound with that amp. Don't be afraid of front end processing.
