For a custom light rifle I'd be starting with something like:
SA stainless 700
Manners EH8 (best light hunting stock I've handled)
Rem sporter dupe barrel from whoever will make it, at 21" and 1-8".
6.5x47
ADL bottom.

Adding an NXS to that mix would probably get you to right at or under 8#.

Or, save the time and some cash and buy a Fieldcraft.

Tanner