love that VO stuff, have had good experiences with them (the vendor, not the shifters, though if they're offering 'em, bet they're fine)
most Shimano bar-ends have encountered can be "flipped" from indexed to friction, believe this may still be the case with newer ones, so if you're not wedded to indexing, that may open up your options, especially with used bar-ends
get the cable stops along with the shifters, they bolt up to the downtube shifter mounts, some have barrel adjusters, too
on a newer note, these will be spendy, but interesting to see R2C (return to center) on 'em...
sram-unveils-new-time-trial-and triathlon shifter