'79 chevy pickup 12 bolt rear Dana 44 front. What are you guys thoughts on this axle combo for a TJ swap?  

Do you want full width axles or are you going to narrow them? Are you sure the front is a Dana 44? '77 & '78 were mixed 10 bolt and 44s but in '79 they were all 10 bolts.  

I would narrow them which I know will get into a great deal of fab, but the price is right and they are in very good condition. I have not seen them in person so I am going on what seller is saying. If it is 10 bolt should I stay away from it? I've heard conflicting degrees of strength on these.  

I don't think the 10 bolt is worth the effort to switch it over. There is nothing wrong with full width axles, just depends on what you want. It's not worth narrowing them.