I think the 48 would be too short. The 8x57 is just about max length for the action. I would think it might work well for one of those short magnums that are all the rage now.

You could make it a 9x57 or 9.3x57 and achieve Whelen-like performance with judicious handloading. I'm getting nearly 2300 fps with 250 Woodleigh's in my 9.3x57, and I haven't started pushing them yet. 2350 will be well within the safe zone, I suspect, and that gets you pretty close. Something to think about.

Right. I think the max is something like 3.1" or so. The WSM would be perfect, or a 308-based case. Or the 35 Remington. That would fit your performance bill.
You can open the action up to '06 length, just like folks do to the k98 for a 375 H&H, for instance, but you're spending a lot of money, when you can just go get a VZ for little and save the trouble, and not risk compromising the strength of the action.

grape creek - which gunsmith do you suggest for this work?

The Whelen is too long, but one of the 284 based wildcats would work, as would the 350 remington magnum, which just about dupliates the 35 whelen. OR...... Have hour local gunsmith do an 8x57 Mauser Ackley Improved on the barrel you have.... which has a much better selection of bullets than the 35 cal, and would present far less feeding problems than the 350 rm or the 284... and would cost you far less to produce, and will be exceedingly close in performance to any of the above, including the whelen

Accuracy Arms here in Anchorage did a really nice job for me on a Yugo 24/47 to 7x57 ackley improved a couple of years ago, along with scope mounts that i didn't have to shim (as opposed to a job that ww did for me earlier). If he doesn't have the reamer, he can rent one in the caliber you want. He has a reputation for quality work and good advise (if asked for it) Super knowledgable and trustworthy. Good guy.