The Hasselblad 501c kit with 80mm lens should go for about $1100.
A 50mm CF lens is about $700 and a 150mm CF is about $500
That's a great travel kit. Buy another back when you can for about $200.
This is exactly the kit I travel with. Weight wise it's about the same as a 35mm body and a bunch of prime lenses. I've never been a fan of zooms. Maybe you should try using primes on your 35 rather than zooms and see how your scans turn out.
If I don't take the Blad then the Linhof gets to go.
Given the resale value of 35mm gear these days you might be a bit optimist about the value of your existing equipment. If this turns out true then your best off keeping what you have and just save up for a larger format.
Walter mentioned the RB67. Great camera and if you are not traveling with it or backpacking (unless your a tri-athlete or sucker for pain) it's a great system. The glass is first rate and much cheaper than Blad glass. Personally I prefer the look of Zeiss glass but that's just a personal thing. A Shen-Hao 4x5 with a couple of lenses and some film holders would weigh less than an RB.