www.microfibertech.com has different microfiber mop sizes in it's commercial section of its website. I've linked to the 24inch size mop head, but you have to buy the pole separately.
http://www.microfibertech.com/24quot-Mop-Kit_p_17.html

The household mop on that website is my favorite mop. It is 16' and comes with the pole and the mop head and is more reasonably priced. You probably would have to cut down the dust mop pad a bit. I love using the washable microfiber pads. I use ones that I got from the store that weren't made specifically for their mop. (Orange Glo makes them and so does Bona. You can get them at Target and Bed, Bath & Beyond and maybe Walmart too.)
http://www.microfibertech.com/16quot-Household-Microfiber-Mop-_p_55.html

I don't know if the links I pasted into the body of this post will work for you. Sorry if they don't.

Here is a link that might be useful: Commerical microfiber mop

YOu can get the mop heads/handles at a store? I checked my Walmart and Target and nothing there was fitted for a velcro-on cover. I didn't check BB&B. I'd rather not buy online, I need to try it out.

I have the Bona system and love it. I bought mine at the local True Value hardware, but I've also seen them at BB&B. I was surprised at how reasonable they are ($30 less the 20% coupon) - it's much less expensive than the throw away system, and better for the environment!

So those velcro on? That's the one store I have not been to yet. What makes it a "system"?