I am interested on the XEB project. The release date was delayed for 4+ years and when they released the public beta, you couldn't run it on hdd or access any settings and the ui is a little different than the PSX's XMB and I don't think that I like it that much so I think that I'll start learning how to use a PS2 DevKit and if I am able to, make an XEB alternative more true to the original.
BTW: XEB is still not released yet, what You saw is a preview version.
Oh, and I made theme already for XEB which icons looks the same. Called DESeR. Release soon with all other.