I think that for the price of the work and parts you have in mind, you could buy a moderately priced Savage heavy barreled 260 rifle, and skip the wait for the .223's barrel to fail.
IMHO a .223 and a 260 in family can complement each other quite nicely. IMHO, the .223/5.56 family are going to be very desirable in the coming years.
While I have, love, and load for accuracy with the .260, it has taken a significant back seat to my .223's since I left off doing the 1000yd comps. I have a Savage 10FCP Predator Hunter .260 and a very nice L-W 28" barrel standing by. A .260 is a delightful LR chambering, but for under 300yd, it also tends to be kinda overkill/less efficient than the .223/5.56.
OTOH, I have three .223/5.56's, a Stag Model 6 with a CMMG 16 Bull WASP upper on standby, a Mossberg MVP Predator, and a Savage 11VT. They get a lot of use; but the .260 hasn't actually been taken out for a full dance card in about two years.
Greg