Theoretically yes! :-)
The skin used by the mobile site is SkinMinerva and is compatible with other skins.
You can enable another skin in LocalSettings.php using
$wgMFDefaultSkinClass = 'SkinBootstrap';
where SkinBootstrap is the class name of the skin you want to include.
You may find this loads a skin minus styles. This is easily fixable by filing a bug against the skin owner to allow their styles to run on mobile.
Not many people have expressed an interest in this, so it would be great to get some momentum and I'm happy to code review any patches you or others may want to submit to improve things in this area.
I wrote https://gerrit.wikimedia.org/r/#/c/261202/ which if merged (ping User:Florianschmidtwelzow) would allow you to use useskin=vector in the address bar and set a user preference 'mobileskin' - it's on my to do list to allow that to be surfaced in the Special:Preferences page...