So i'm designing a Monk/Rogue Combination and using the Ascetic Rogue feat from Complete Adventurer. Now the only problems I can seem to come up with is that Flurry of blows does not stack with the feat. Thus you would have to take the feats seperately (TWF,ITWF, GTWF) for it to work. My question is flurry of blows uses the monk level to determine attacks, would you still be able to take ITWF since you 'gain' it as a first level monk?
Ascetic Rogue
You have gone beyond the bounds of your monastic training to incorporate new modes of stealthy combat. Although your fellow monks may frown on your methods, none can doubt that your diverse training has improved your ability to strike precisely and bring down
your foes quickly.
Prerequisites: Improved Unarmed Strike, sneak attack.
Benefit: When you use an unarmed strike with a sneak attack to deliver a stunning attack, you add 2 to the DC of your stunning attempt.
If you have levels in rogue and monk, those levels stack for the purpose of determining your unarmed strike damage. For example, a human 5th-level rogue/1st-level monk would deal 1d8 points of damage with her unarmed strike.
In addition, you can multiclass freely between the monk and rogue classes. You must still remain lawful in order to retain your monk abilities and take monk levels.
You would not gain the benefit of ITWF or GTWF unless you are an 8th or 15th level monk.
In my opinion you can still take the feats as long as you apply for the prerequistes, if you only want to use TWF in flurry of blows I'd say you do not have to take TWF since you get it in FOB already.
You would have to take ITWF and GTWF though, since you only fullfill the prerequiste TWF while using FOB you can only use those feats in FOB as well.
In short you can take it if you spend the feats, but it will still be limited by FOB thus slightly less versatile than the actual feats.