Works on the front panel started but it will take quite some time- epoxy needs at least one day curing before I can start any work on it, and I have to go to work sometimes.
Cut out for the dvd tray is done. Dvd panel has about 1 cm distance from the front panel so I have to add some walls to make it look better:

However after sanding one of the parts fell off (my bad, I forgot to scratch it before gluing) so I had to attach it one more time:

This time polypropylene part is held against the edge using an acrylic leftover and old telephone cards (when bent they provide quite some force).

Front after sanding both longer edges to size:

And after adding shorter walls (from behind):

Both shorter walls are covered with a layer of epoxy, I'll sand them down when it's cured. Of course visible regions of these wall will be of course covered with black paint.

I made a 2h test run- 1h of music and 1h of video, both streamed form miniDLNA server.
Running OpenELEC 4.1.6.0 since it supports my remote and doesn't include fan service (so only passive cooling was used)

Temperature
Music playback- most of the time 41 Celsius with top of 42 Celsius.
Video playback- most of the time 50 Celsius with top of 52 Celsius.
Notes:

-fan was not used
-case was closed and standing in vertical position (on the side)
-video files used in test have different resolutions (480p to 1080p), compression (divx/xvid, h264, DVD) and bitrates

Wifi
Extension cable works fine, no problems with signal strength or dropping

MCE remote
I have to relocate the antenna, range is ok only when operating the remote on front of the HTPC. In 5.x builds of OpenELEC there is a bug which prevents loading keymap modules, it's being worked on.