Is it possible? With custom text just like a roadsign in the world? How ?

Hmm...

Know anything?

I don't have any idea

ok ;p Maybe someone else?

Make a new texture with your new sign and appy it as texture set to one of the vanilla signs.

Search the forum for "retexturing" or "reskinning" if you don't know how to add them to the game,

Here is a photoshop template from my WIP with a layer to cover the text of an original roadsign and then add new text.
http://mods.jo-ge.net/sk/dl/roadsigns01.7z

Use this texture as a texture-set to override the orignal roadsigns for Morthal Karthwasten and Winterhold

It then looks like this in the CK: http://mods.jo-ge.net/sk/dl/signs.jpg


the PSD uses this font for my new text: http://www.dafont.com/holmes207.font