Brands like Arda, Epic Cosplay, Five Wits, and ebay stores such as Moe Mall, Cosplay Wig, and Ayanamisatoru all sell shorter, black, spikable wigs. You may have to trim the hair before gathering the spikes and spraying them with hair spray.
You also have two options for how you want your wig to look: 1) natural spikes, as seen on this cosplayer
; or 2) unnatural spikes, as seen on Malindachan
Look up wig spiking tutorials on YouTube or deviantArt on ways to trim and style wigs this way. If your wig is also heat resistant, you can hit it with a blow dryer for additional staying power. Hope this helps!