Ron, it sounds like you're trying to do the same thing I do, which use a single machine both for your design prototyping and for your production.
This is a compromise, but it can work. In my case I've got a 3 axis CNC BP type mill. Prototyping parts for your own product line is pretty different than "one off" job shop prototyping, when your doing it yourself the part is going to come on and off the machine a lot of times for testing, measuring, staring and tweaking. This makes an open machine more attractive, especially a BP type machine where you can nod and tilt the head and hang and extend parts off the table.
Trying to do this kind of "interactive" prototyping on a full VMC is difficult and wears you out, and there are some things easy to do for prototyping on a BP mill that you would have to make a special fixture to do on a full VMC.
But of course it flips around when the design is done and you're ready to make a production run. Now you really will wish you had a fully enclosed machine with an automatic tool changer (ATC) and full coolant.
For production what I do is use a micro-drop system (by Trico) instead of full coolant, and although I'm stuck with manual tool changes, I use the Royal EasyChange system to at least speed that up, although for aggressive milling I have to use full holders, the EasyChange system is too flimsy for that. And of course chips get everywhere, but it works, and right now I can't afford a full VMC.
In fact I don't even currently have a CNC lathe, for parts that need machine controlled turning, which fortunately in my case are pretty small, I stick a R8 4" 3jaw chuck in the spindle of the mill, put the blank stock in there and use multiple lathe tools bolted to the mill table gang style. This works surprisingly well if you can live with the size limitations, and is actually more production oriented than when milling on the machine as you don't have to do any tool changes, you just program an offset to move to the next gang tool.
I've been kind of hacking this so far by clamping lathe tools to the table, but its working well enough that I'm making a gang tool holder bar that will use pins to reference to the slots on the table and thus will be really fast to take on and off the table and will make setting up the offsets really easy, each tool is on center with the slot and is spaced exactly 3" apart.
I also have my vise on a pinned plate so I can move it on and off the table really quickly without needing to square it, and the same pins are used to mount my product fixtures square to the table. So in about 2 minutes I can swap from lathe, to mill or to vise work without having to square anything.
If my products grow enough I'll either add a VMC (the Sharp 2412 is looking good to me if the $ really starts to flow) and keep my current machine for the proto work or upgrade to a Haas TM1 with a tool changer and use it for both operations. I view a TM-1 with a tool changer as probably the best "combo" (prototyping and small production) machine available, at least for the money.
Good luck-
Paul T.