Hi Asmund,
Depends what you're trying to do. I've just being working on coding custom widgets to group related fields horizonally. I based my work on the currency widget (acs-templating/tcl/currency-procs.tcl) to get a widget with an entry box and drop down entry box using the on_refresh methods. - If this is what you're trying to do I can let you have my code as an example.
Just to display a standard ad_form arranged horizontally would require custom coding of the ad_form method.
cheers
Mattthew
