I've read somewhere that the Kef R100s are similarly spec'd to the LS50s. I've also considered them for awhile since they do have grilles. Glad to hear your LS50s are playing well with the Marantz though!
Currently I'm rocking a pair of the German-made Kirksaeter Silverline 60s. They are very musical and have excellent controlled base for their size. The cabinets are MDF so I'm not concerned with my little one playing around the speakers. Perhaps when he's a little older I will get more serious about upgrading to Kef's or Totems.