I think u will be better off buying a pre programmed chip then u can just do the instillation of the chip yourself. Ill link u a website that i think will accommodate your needs for a rapid fire controller. This is the only company I know of that still do old school rapid fire where u have rapid fire on tact switches freeing up your triggers to remain stock or u can get ones that operate off the triggers as well. These chips + shipping fees will be about the same price maybe a little cheaper than building your own programmer and buying 12f683 chips to program.
Here is the link.
http://www.maddogcontrollers.com/ Check it out and let me know if this is what your looking for.
Just go to Xbox 360 fixed rapid fire chips or Xbox 360 adjustable rapid fire chips. I would strongly suggest getting adjustable RF chips. They have the old school & new school styles of rapid fire so this should accommodate what your looking for.
Its beginner level modding stuff. If you don't know how to solder just YouTube how to solder Xbox 360 controllers. Almost every company that sell DIY chips will list a instillation tutorial and will help u identify what model of controller u have. If you don't like these chips then just look on eBay and u will find thousands of companies selling these basic RF chips for around 7 to 20$.
Good luck. I hope this answers your questions. Just remember it will cost u about the same to go this route than to build a programmer and order 12f683 chips. The disadvantage is your selling yourself short not building or buying your own programmer and using acid mods opensource hex's. The hex files in these forums are "in my opinion" better than these cheep eBay companies. Your more than likely pay 20$ on eBay to some kid that's using these acid mods free codes for their own profit anyways LOL.
Here is a perfect example of a company thats selling hazers rapidfire RF hex as his own for like 50$ that would only cost u a doller LOL.
http://www.diablohomods.com/Pages/Controller_Mods.aspx