This advice is based on my own experience.
Just about any kiln can "crossover" on metalwork vs
enameling/lampworking needs. Really, in my experience, the only time
you'd need a seperate oven for metal is if you decide to cast, then
you'd need a special burnout oven that can be ventilated while
holding heat in.
You could check out used kilns in the back of bead magazines, if
cost is a concern. Then you could prove your point beautifully when
the poor thing falls apart from "overuse."
My experience is this: get what you need to get, regardless of the
cost. If you compromise on your tools, frustration will keep you
from getting anywhere. Especially if you try to make a tool do
something it's not meant to do- it'll just wear out faster. (Exhibit
A: the dremel drill that caught fire.)
Because what will happen (invariably) is that you'll save money
initially on the "compromise tool" and then you'll spend more
getting what you should have gotten in the first place.
Personally, I recommend the Neycraft Fiber Furnace. It does burnout,
enameling, and heat treatment/annealing. It costs $560 from Kingsley
North (1-800-338-9280). It covers all possible needs, for about the
same price as a decent sized kiln that could be used for everything
However, if this isn't an option for you because of concern about
cost, I have a good used kiln that needs a home, and I can give you
a great deal.
I wish you luck!