Ok the t-board will run either breakbeam, or bouncebeam eyes. bouncebeam being the single unit, and breakbeam being the dual sided unit. the stock dragun boards will not run either on a dragunfly without the addition of a dragun eye board. But the eye logic SUCKS doing it that way. MUCH better to get the t-board. Plus you are wanting the extra firing modes, which the stock boards wouldnt give you
UNFortunately, I'm not gonna be much help on being able to tell you about some places that would do the body milling for you, for the turtle-ing. If somebody around here cant give you some suggestions, you might try in the voided warranty section of the boards http://www.pbnation.com/forumdisplay.php?f=231
or the autococker sections. Not sure which one I would recommend trying first. Probably autococker.
The threading for the pump arm will match up to any A/C parts, its just the length that is the factor. Its a bit shorter than a standard A/C arm. However, if you're getting it turtled, they will have to cut and rethread a part of the pump arm anyway.
Feednecks are kinda limited. You've got your choices of ones made either specifically for draguns http://cgi.ebay.com/Black-Dragun-Gun...QQcmdZViewItem
or clampers made for the Odyssey Wrath. (couldnt find any of those). A spyder feedneck like this- http://cgi.ebay.com/Blue-Spyder-UFD-...QQcmdZViewItem
could work, but you'd need to file down the tabs for the retaining screws a little bit, in order for them to fit into the body of the d-fly correctly. Which is basically those feet at the very bottom of the neck.
Hope this helps