I doubt that the typical commercial spouts will fit but you CAN reuse the cap, or use the spout on a bottle with a standard-diameter top.
Here are other alternatives: https://www.amazon.com/s/ref=sr_1_2_hso_sc_smartcategory_4?rh=n%3A1254736011%2Ck%3Asmall+squeeze+bottle&keywords=small+squeeze+bottle&ie=UTF8&qid=1468257365&sr=8-2-acs
