FYI, crypto-trade.com now supports direct XPM/PPC and XPM/USD trading:
https://crypto-trade.com/trade/xpm_ppc
https://crypto-trade.com/trade/xpm_usd
crypto-trade now supports 3 trading pairs for XPM and 2 trading pairs for PPC, including direct USD trading for XPM. Thanks neotrix and team for the excellent support!