IF you are looking for a MF option with tilt shift the Fuji gx680 is a good option.
All the lenses are tilt shift and there is a kit that lets you put a digital back on it.
There is even a shift adapter back that lets you shift the back giving you a virtual
sensor twice the size while still doing your composition on a full 8x8 focusing screen.
You can also go wider that a two frame stitch by also using lens shift to go a bot further.
The Fuji gx680 is also inexpensive, but it is rather big.
However the widest lens is a 50mm. That is very wide on a 6x8 negative, but not that wide on a digital back.
If you are interested in more info on the GX680 I can send you PDF files of the manuals and brochure/catalog.
PM me your email and I can send it to you.
As far as your budget goes you would get quite close with a Fuji GX680.
The version I of the Gx680 does not cost much and there are many nice cameras on ebay.
There is a gx680 with 100mm lens and back going for $ 399.
You could get a nice Phase One P25 back for around $ 4,000. Nice simple back.
The adapter kit is about $ 800 with the control box.
Some 4x5 film photographers have gone to D800E and tilt shift lenses.
Well known landscape photographer Jack Dykinga has switched from 4x5 view camera to a Nikon d800e and all three Nikon T/S lenses. http://www.dykinga.com/gear
. That would fit your budget and smaller than the Fuji gx680.
Also here is an article where the D800E is compared to the largest MFDB and the article talks about large prints.
You should find it interesting because the lens used on the Nikon is a 24mm tilt shift lens.http://www.circleofconfusion.ie/d800e-vs-phase-one-iq180/