Hi there
First of all, thanks for the great component!
Some questions from em though:

1. mysql size
After installing database size jumped from 3mb to 39mb - I believe it does seriously harm server performance, no? mysql eats resources a lot..
1.2. Did you see detectmobilebrowsers.mobi/ they provide free php code to detect mobile phones. I used them on some modules.. worked well and looks like it isn't that "heavy"?
Possibly you can try implementing it? Or use some wildcards in mysql? Or provide a "lighter" version with popular devices ONLY?

2. I tried to emulate Blackberry smartphone via Firefox plugin addons.mozilla.org/en-US/firefox/addon/59/
website doesn't open.
Firefox window pops up - "You have chose to open which is a: text/vnd.wap.wml - What should firefox do with this file?"
Although I can see that others come to site using Blackberrys (via webserver logs) - Can I be sure that this is Firefox plugin issue?
Is there any better way to test compatibility on Blackberry?

3. mobile_smartphone template
I actually replaced it with iPhone template - I like that there is better navigation
- HOME and BACK buttons
- Site MENU buttons are bigger too
Possibly you can improve it in the future

4. What about additions to page URLs like ?device=xhtml
Are they handled OK by search engine robots?

5. Google ads
Not sure why is this issues but Google mobile ad unit 320x50 is outside the margins on iphone template when placed inside text.
Above/below text it fits perfectly well.

6. Спасибо!

Our device detection is quite sophisticated and includes information such as screen size, supported image formats, scripting support and so on. Mysql can handle a ~40MB database just fine and it is mostly used for reading so you probably wouldn't be able to tell it is even there.

You'll need this addon to display content with text/vnd.wap.wml http://wmlbrowser.mozdev.org/