Have some new parts on hand but need new frame - frame swap reasonable? or sell and purchase new bike? Purchased my first "decent" bike, a Motobecane 700HT about 5-6 years ago as a 'gateway drug' of sorts for myself to get into XC biking. Ended up using it for commuting for a few years as well.

Over time have upgraded both front and rear discs with Avid BB7 (160/180mm) and tried to keep everything clean and well serviced. Frame got beat up a bit commuting (locking to outside bike racks) but just cosmetic. Bike still runs pretty well, shifts great - front gears can be a little slow but that might just be typical Deore derailleur (I have XT in the back and still run like new). Front fork (Dart 2) lockout is broken and I think the rebound is starting to get sluggish. I've replaced several other minor components over time as well. 

I currently have on hand:


A brand new Rockshox Reba RL 120mm TAPERED 15mm Maxle lite (steer tube has been cut down just a little bit, should still be plenty long, but affects resale)
A brand new Mavic Crossride Disc wheelset (15/12mm through axle)  


These are of course, utterly useless to me right now. I actually did try to mount the Reba fork to my bike using a specially designed headset from Cane Creek and while the fork "fits", it just barely rubs on the inside of my headtube. No dice.

So my question: Would I be better off liquidating everything I currently own and purchasing a new bike, or would it be a reasonable endeavor to port my current parts to a new frame (waiting for a good deal online)? I am not sure how 'compatible' my entire parts list are for modern frames and considering age whether I would be better off starting from scratch. For consideration, I am confident in my ability to swap components over myself, so I won't be having to tack on cost of LBS to do it for me. 

I found a local that is selling Dartmoor Primal frames sub $200, which sounds like it might be a winner for me - being 650b or 26er compatible I like the idea of upgrading to 27.5 wheels as a down the road upgrade. I expect to have to purchase some new minor components to handle this swap - probably new bottom bracket (? I am fairly unfamiliar to the different specs on BBs) and seatpost - not sure if frame comes with headset but I'll assume I'll need a tapered headset as well as all new cable. Is this reasoning sound? Or are there likely more parts that will need to be changed?
Well, it depends…

Would you be happier cleaning a bunch of stuff out and getting a shiny new bike that reflects all you've learned? One that will "just work," or

Would it be a fun project to build up a bike from scratch? Would it feel good to know that you'd "built it yourself?" Do you have the time for the project? Is it ok with you to get stuck and make some mistakes – probably "wasting" some time and/or money?

If you decide to build, there are likely to be some unexpected "gotchas" along the way. So it is worth doing some reading and searching to see if others have run into similar problems. Sheldon Brown has a good piece on Upgrading Older Road Bicycles that may help you start thinking about the possible problems. Overtime the morass of bicycle standards has sorted itself out (a bit) so some of the problems that he mentions may not be issues. If you're looking at a frame you may find that the builder/seller publishes the key specs so that you can buy the correct parts. The specs will help you identify where the problems may lie. Some of the ones that come immediately to mind are:


Frame size and stem type, this decides if you can use your existing stem and the length of the stem you'll need.
Rear dropout spacing. This will decide how easy it is to use your old wheels.
Seat tube diameter (affects seatpost size and the front derailer clamp size).
Brake type and reach (distance from the mounting bolt to the rims, this is mostly an issue for caliper brakes).
Tire clearance.
The bottom bracket. It used to be that frame builders were tending towards 68 mm wide bottom brackets with British threads, but now there is a whole new generation of bottom bracket designs, so you may find that you'll either need to pick a frame to match your old one, or get a new one.


I tend to lean towards the build side, but that's partly because I can't afford the bike I really want…