Just like the title says...I have something with some dings I would like to fill and re-finish. Is there any sort of metal filler that will take bluing? Or another alternative that looks as good as bluing??

Thanks.

There is no filler I know of that will either take bluing or parkerizing, or will take a chemical finish at all.
Most fillers are some sort of epoxy mix and won't take any chemical finish.
The only really practical way to fill imperfections and use a chemical finish over it, is to have a good gunsmith/welder weld up the imperfections and resurface the area.  This will allow bluing or parkerizing, but the welded areas will usually show through the finish as blotches due to the heat and different alloy used as welding filler.
You also have to be very careful about heat on heat treated gun parts.  You don't want this attempted by your local garage welder.
Having this done by someone who understands the hazards and necessities of welding guns costs money.

Probably the easiest method is to use the filler material sold by Lauer Duracoat and then apply a coat of the Duracoat over that.
The filler material is specifically designed to fill pits and imperfections in guns.

Duracoat is a two part mix epoxy "paint" that comes in many colors and is an extremely tough air-cure product.
It's used widely as a finish for guns.

http://www.lauerweaponry.com/

the only one i know of is weld.....but then you'd have to machine it down, re-heat treat it, and then refinish.

advntrjnky