The release of Pagemaker 6.5 Plus in May 1999 was Adobe’s attempt to refocus PageMaker on to the corporate market (where it was competing with MS Publisher), while they were developing InDesign for the professional end of the market (where it was competing with Quark Xpress). Quoting from a press release at the time:
PageMaker 6.5 Plus has been enhanced with new features that make it easier for business publishers to tap into its professional power. Enhancements include:
• Photoshop 5.0 LE, a limited edition of the world standard photo design and production tool, makes it easy to incorporate and edit photographs.
• Acrobat Distiller V4, allowing creation of PDFs
• Adobe Type Manager, for managing fonts (140 Type 1 fonts included).
• Over 4,700 professionally-designed stock illustrations in Adobe Illustrator(R) format, hundreds of design templates and 300 high-resolution, CMYK images.
• Picture Palette (Windows only) offers easy browsing, viewing, searching and cataloging PageMaker 6.5 Plus image and template files.
• A Windows plug-in that creates a familiar, icon-based toolbar with shortcuts to commonly used PageMaker features makes it easy for Microsoft Office users to be immediately productive.
• A Microsoft® Publisher 97 and 98 file converter (Windows only) for Microsoft Publisher users migrating to PageMaker makes it easy to use of previously created materials.
• The PageMaker 6.5 Plus Getting Started Guide includes design tips developed by well-known graphic design expert Robin Williams, author of “Design for Non-Designers” to provide business publishers with extra help for developing professional quality materials.
I have no idea where you could buy a copy of PM 6.5+. Guess that depends a bit on where you are located.