Finally I decided to take the KS R-4G dedicated server from the OVH provider (
https://www.ovh.it/server_dedicati/kimsufi.xml).
I write here a little note for anyone looking for infos in the future.
My feedback is very positive. Not only the costs are reasonable (you can find a server for any budget), but also their support and expecially their control panel are very good.
First of all you can choose to install your favourite linux distruibution (slackware included!
) at no additional cost. In case you don't like the default partitioning you can always reinstall everything via control panel, partitions and raids included.
And you can do an hardware reboot whenever you want. When you get a kernel panic or a boot fail the help desk receive an advise and they will boot your machine selecting the default kernel from the grub menu for you. Of course this is quite important if you have to patch the kernel from remote.
The ticket time responce is also acceptable.
So my post installation phase (the one that also serves as a test for the help desk) is ended, and at this point I can recommend this provider