I put my DS in Robeez - really soft leather slipper type shoes, he was crawling and cruising in these from 7 months so didn't slow him down at all.
(there are various other brands which friends have had which work just as well i just thought the Robeez were so cute)
these were really good on the wooden floors as he didn't slip much and were difficult for him to pull off so more successful than many other baby shoes
but i think that you should only really go into more sturdy shoes when they are walking properly