I want to build another random gun. I like to start with a magazine and work backwards from there and this time I'm aiming at a .44.

As far as I can find my only real options are:

Ruger rotary mags for the 77/44 96/44 and 44 Deerfield
Desert Eagle .44

Anything I've missed?

Well if those are my only two options then I'm limited indeed - Desert Eagle mags seem entirely out of stock currently.

Ruger's rotary mag it is.

I don't know if you're just talking about current production or not, but there is the Universal Vulcan 44 Mag magazine and LAR Grizzly Mark 4 44mag and LAR Grizzly Mark V 44 Mag magazine.
All three come up for sale on GunBroker on a regular basis.

Tony

I like that Universal Vulcan 44 magazine - but yes I'm trying to stick with current production. I've ordered a Ruger magazine but only one for now. We'll see what develops.

I have always thought a ruger deerfield 99/44 modded to use desert eagle mags would be so much fun! The model 99/44 is the newer one that has the mini-14 style action.
I would think the model 99/44 might be easier to convert since it already uses a detachable mag (the rotary mag you speak of). Unlike the older model 44 carbines that use a tube mag (and look like a big 10/22).

I wish ruger would bring back the 99/44 and also make it in 357 mag. I know they would sell cause all you have to do is look at the prices these things are brining on gunbroker. They were stupid prices even before the current panic (I have been looking at them for a couple years, hoping to find the right one at the right price).

My desire for a Deerfield is exactly why I'm wanting to build a .44 magnum semi-auto! I'm not paying that much - and honestly the styling isn't to my tastes. I figure I'll build the gun using the rotary mag as a proof of concept and to refine the bolt weight and such and then most likely I'll end up having to make a mag or two.