Soapbars have so many sizes. almost all brands have the replacement, such as bartolini, EMG, Basslines, lane poor and so on Bartolini has so size for soapbars
No, they're not all the same. Look at Bartolini's website, at http://www.bartolini.net and check their online catalog. They make tons of sizes and shapes. Seymour Duncan also makes bass soapbars. DiMarzio makes some pretty cool looking ones that have mahogany covers and appear to be a similar size to some others on the market. Hope this helps.