arky,
To convert to a 40, the 270 and 30 caliber 1895's need to be rebarreled (or so I'm told). Anything over a 35 caliber and there just isn't enough barrel there. I would think any good gunsmith could do the rebarrel job for you, so labor rates would vary. Douglas Premium barrels are running about $250-300 these days, I think. I'm not sure what the other Douglas barrels are running or other brands. I think Shilen, Hart, Kreiger, Lilja, etc... are quite a bit more expensive. If you rebarrel, you have the sight issue to deal with also. Cutting the barrel down and recrowning, adding sights, adding a sling swivel (if desired), etc... If you have a gunsmith you trust to rebarrel and chamber for whatever you are looking for, ask him to give you a quote. Also, if you are looking at a 40/06, check the 400 Brown-Whelen and 411 Hawk. Both are improved versions of the 400 Whelen. The improved versions allow more insurance headspacing and offer a little better performance, though not sure how much is needed.
$795 seems a bit high to me. If you search on GunBroker or GunsAmerica, you can find NIB 270's and 30/06's for a little less. I picked up a NIB 270 for $400 last year.
For what it is worth.