Visual MainWin - Provides implementation of Win32 API (including COM API) on UNIX platforms (AIX, HP-UX, IRIX, Solaris, Tru64). By MainSoft Corporation. - http://www.mainsoft.com/products/index.aspx
ActiveX/COM Inspector - Allows inspect and execute any ActiveX control. By oakland software. [Commercial] - http://www.oaklandsoftware.com/product_3.html
TLB2HTML - A COM and ActiveX reference documentation tool, providing HTML Help authoring for C/C++ and Visual Basic, MSDN-like, documentation. [Shareware] - http://www.glista.co.yu/tlb2html/
COM for OpenVMS - Compaq's implementation of COM for OpenVMS platform. - http://www.openvms.compaq.com/openvms/products/dcom/
Wind/U - Toolkit for creating native UNIX/Motif (Sun Solaris, HP-UX, IBM AIX, SGI IRIX, Digital UNIX, Siemens Nixdorf Reliant UNIX), OpenVMS, and OS/390 applications with the Microsoft Win32 API and Visual C++. By Bristol Technology Inc. - http://www.bristol.com/windu/