Good on you Kevin, you certainly have got your monies worth out of that 1100d. Dam good camera that one, I admire what you get out of it. I think you'll have to wait until it dies to get your deep sky cam because you won't be able to sell it with the shutter count value it must have!
With the DSLR we can take shots of friends and family during the day and deep sky Ha nebulae at night. Can you do that with a dedicated Astro cam?