I could see an intellectual chi talent for a martial artist who spends time meditating on those specific skills rather than improving general IQ, etc. But the double bonus feels wrong. I think there's 12 mental chi skills, so just go RAW — drop it to 10 points and just +1/level?
Another approach that martial artists take is becoming one with the universe through mastering forms and katas. How about something analagous to the Swashbuckler's Sheer Speed perk?
Perfect Stance†‡: You must specialize in a non-DX-based chi skill; each requires its own perk. You have learned the perfect stance and movements to channel your chi or to sense chi flowing around you for one specific effort, allowing you to learn the chi skill as if it were DX-based, instead of the usual HT, IQ, Per, or Will-based.
† Requires specialization. ‡ Permits multiple levels.
This path will surely end up cheaper than a mental talent making up for the difference between DX and IQ, but when treated as a combat perk (p. DF11:11) will take longer to accumulate and encourage players to put points into skills rather than just attributes or talents.