You make a good point and those are things I've thought about.
My concern isn't so much the telescope depreciation. That was only one thing I was thinking about.
I bought a brand new Canon XL2 digital camcorder about 5 months ago. I have about $6,000.00 invested into it with the extra batteries, filters, special bag, various add-ons, etc, etc. After using it, I found out its a real pain in the back side to have to remove the lens (to prevent breakage when hauled), pack it onto the ATV, drive a mile, take it out, install the lens, shoot, remove the lens, pack it away, drive a mile and then repeat the process. I spend a lot of time doing things that have nothing to do with filming.
So I bought a new High Definition Canon XH A1 last week, which has a permanent lens (yet better wide angle and zoom) and which is smaller and easier to pack away. Now that I have no lens to take off and put on I can spend more time shooting and less time fighting the equipment. And the footage is better and higher quality to boot. When I sell the XL2 I will take a beating on depreciation. Not only that...none of the accessories I bought for the XL2 will fit the A1. They all have to be sold, too...at a loss.
Had I bought the right camera the first time, I would have saved money, hassles and frustrations and saved a lot of time.
My concern is that I don't want to buy a telescope and then later have to sell it and take a beating on it. Its not worth the time, hassle, dealing with replacing accessories, shipping it, etc...
I know its not always possible to get the right thing the first time and no matter how hard you try you still may end up selling and replacing. But that usually only happens when I don't spend enough time up front to understand my needs and understand the products well enough. I've very seldom gone wrong when I've tried to buy the best.
The best doesn't mean the one that costs the most, either! I'd prefer not to spend more than $6k or $7k on a telescope and even that is a lot.
You suggested a High Mag SCT for DSO imaging. I'd be happy with that, but here is my concern. The Meade RCX400 won't work on a GEM. The LX200R suffers from image shift problems and its seems to be a matter of luck if you get one where the image shift is minimal. Here is one (of many) quotes I've read about the Meade problems:
So I decided to get the LX200R, which also has good optics, but is mechanically the same or worse that the LX200 design. I can't tell you how disappointed I was. The optics are pretty good, but the image shift is intolerable. The mirror lock DOES NOT WORK! Even with the mirror in full lock position, the focus changes with elevation, and probably temperature as well. The result is that you have to re-focus with each object.
I have seen a few LX200s with very little image shift, but most of them are excessive, at least for imaging. Be very careful to inspect the tube for image shift before paying any money. The problem is that if you get a bad one, you may have a lot of trouble getting Meade to fix it. A friend bought an LX200 OTA and it has about 6-7 Jupiter diameters of image shift. It has been back to Meade twice, with no noticeable improvement.
I suspect that even though Meade sometimes makes tubes with small image shift, they do not know how they do it. They do not seem to be able to remedy the image shift.
I wished I had got a C-14 because at least you can get the mirror lock that keeps the mirror from changing position.
Dr Clay suggested a C14 to me about 2 months ago. I researched it for a few days. Cloudy Nights doesn't have a celestron forum for the C14, there seems to be very little community support for it. I thought the photos from the LX200R were nicer than those I found from the C14. So I was disappointed. Also, there is a rumor about Celestron and their optics going downhill. That seems to be supported, too, by a review a french Astronomy magazine published after they tested the 9.25 optics.
That kind of left Celestron and Meade out of the picture for me. Others have said that the Taks seem to be more of a fad telescope and that they aren't really all that great.
Grrrrrr I know you can't believe everything you read. But I think I read too much!!!! Anyway, I've never heard one negative about the RCOS telescopes. I've heard glowing reports on support and performance.
12.5" RCOS Telescope
Paramount ME Mount
Pilot's Cross Observatory
45° 15'48.85"N, 93° 21'30.91"W
Silently one by one, in the infinite meadows of heaven
Blossomed the lovely stars, the forget-me-nots of the angels. -Henry Wadsworth Longfellow (1807-1882)