I just came back to edit my query after realizing I forgot about the blocking filter, your post confirmed it, looks like it will be no less expensive at all.
The Lunt 10cm etalon, to be front-mount on any scope, is still listed on their web site. It is probably not less expensive (maybe more expensive) than a dedicated solar telescope, but it takes up a lot less space in the dining room and all the peripherals can be immediately added or subtracted. In my case, Lunt first supplied me with a 10cm etalon and an adapter the fit onto the end of my Tak. They did a beautiful job on that. At the time I was undecided about double-stack due ot the cost. But after using the single-stack, I decided i liked it enough to go with a double-stack. As you are probably aware, every accessory for the Tak is expensive. So by putting the etalon on my Tak instead of getting a dedicated solar scope, I am able to easily switch back and forth and not be carrying around twice as much gear, and I can use the Tak extender and reducer as desired, and not have to duplicate other accessories (Pegasus power-box, electronic focuser, etc).
I should also mention that i'm a scientist by training and for most of my career I've been building or modifying commercial optical and electronic instruments. It's what I enjoy doing. Others may be more focused on the final image, but, for me 'getting there is half the fun'. So from a pure cost standpoint it might not make the most sense. But from an enjoyment/satisfaction standpoint, it does. If I was retired ( just a few more years to go) I'd probably be building the OTA from scratch.
Edited by hamers, 12 May 2021 - 10:52 PM.