Chevy classic body on ford, chevy or dodge diesel frame question

[bufmatmuslepants]

Just organizing my thoughts kinda, I was up for hours last night riddling this around in my brain because my 6 month old would NOT stay asleep.

I've always had this crack pot idea to put a classic body I love on a modern chassis. With the growing family my original idea of a 67-72 on a 3/4 ton reg cab 00-06 chevy frame with the 6.0 gas motor has grown to realize I need a crew cab. Crew cabs with the added weight I feel like a 6.0 gas won't cut it anymore for my mpg and towing needs, so I was thinking 73-91 or 95-99 crew cab on a duramax chassis. Problem is the duramax I can afford would be an lb7, maybe an lly, but any under 150,000 mile crew cab duramax is still expensive. The 90s 12 valve and 24 valve dodges would be a good candidate, but they ride like crap and dodge autos are garbage, and I need an auto for my wife to be able to drive it while on vacation if we are somewhere that nobody else brought a car. I've been looking into the 6.0 diesel fords, and it seems that if you do the EGR delete and head studs, as well as the bullet proof diesel air to oil cooler, they can go 400,000 miles easy, with a B50 of 350,000 miles. The duramax only has a B50 of 200,000 miles, and if you just go on autotrader you see very few duramaxs with over 250,000 miles, yet tons of powerstrokes with over 350,000. Dodge has the cummins and we all know it can go 500,000 miles easy, but the rest of the truck falls apart around the motor. Other thing I like about the 05-07 6.0s is the live front axle with coil springs, and the 11,000lb gvwr.

99-07 ford wheelbases
Ext cab short bed 141.8"
Crew cab short bed 156.2"
Extended cab long bed 158"
Crew cab long bed 172.4

01-06 chevy wheelbases
Crew cab short bed 153"
Ext cab long bed 157.5"
Crew cab long bed 167"

95-99 chevy wheelbases
Crew cab short bed 154.5 (subtracting short bed from long bed)
Ext cab long bed 155.5
Crew cab long bed 168.5"

73-91 chevy wheelbases
Crew cab short bed 146.5 (subtracting short bed from long bed)
Crew cab long bed 164.5"

94-02 dodge wheelbase
Ext cab long bed 154.7"

02-06 dodge wheelbase
Crew cab long bed 154.7"

From these numbers, you can see a 95-99 chevy crew cab short bed would fit perfectly over the dodge long bed frame from both generations.
The 95-99 chevy ext cab long bed fits perfectly over ford ext cab long bed.

Everything else requires either modifying the frame or the position of the wheel wells in the bed, since I still want to put a cap on it. To get my crew cab, the dodge is the best choice, but they ride so harsh and I'd need to rebuild the tranny, which in all honestly costs as much as injectors on an lb7 or the bulletproof kit on the 6.0, about $3000. I could in theory do a 73-91 on a ford ext cab long bed frame if I cut down the long bed sections before and after the wheel wells on a long bed, which in my mind is easier than cutting the frame, parking brake cable, brake lines and driveshaft.

I'm just throwing ideas around and organizing them now. A 94-02 cummins can be had for $6-10,000, 6.0 ford from $8-12,000, lb7 for $10-14,000, 02-06 ram for $12-15,000. 7.3s are cheaper but I don't want a leaf sprung front axle for the ride and turning radius.

Any input? The purpose of this truck would be vacations, towing my Camaro to tracks as far as 1000 miles away through the mountains (VA to bowling green, KY), towing my boat, and DD duty in winter on 70 mile round trip.

Pros of the duramax: smooth ride with independent front suspension, quiet, Allison trans
Cons of duramax: dont seem to last much past 250,000 miles, and the ones I can afford already have 150-200,000 miles, injector issues on LB7, head gaskets and bigger cooling system needed on LLY

Pros of the 6.0 ford: high GVWR, live front axle easy to lift in future
Cons of 6.0 ford: needs head studs, BPD oil cooler, and still can have problems

Pros of 94-02 dodge: Cummins motor, great fuel economy, cheaper initial buy in
Cons of 94-02 doge: great motor wrapped in a crappy box, trans would need rebuilt, rides like crap

Pros of 02-06 dodge: Cummins motor, great fuel economy, better ride
Cons of 02-06 dodge: still a crappy box, still a crappy trans, high initial buy in