You can use any of the older Beovox speakers but Beovox 1200 would be
the obvious choice.
There are no less than three different versions of the Beovox 1200, any of
them will work fine.
Of the panel speakers, the 1600/1602 and 1800/1802 series spring to mind but
the slightly later P30 could also be considered.
The panel speakers are generally rare.
Martin