I have finally found a satisfactory replacement for the Microsoft Trackball Explorer and it is the Elecom Deft Pro – Jonah Lee Walker, Editor, Colorist and Motion Graphics
Microsoft Trackball Explorer USB Optical Trackball (D68-00007) for sale online | eBay
Amazon.com: Microsoft Trackball Explorer : Electronics
ヤフオク! - マイクロソフト トラックボール エクスプローラ...
Microsoft Trackball Optical 1.0 PS2/USB Compatible Mouse X05-87475 Red Ball | eBay
Microsoft Trackball Explorer - Trackball Mouse Reviews
猫のトラックボールルーム ~Micrsoft Trackball Explorer 2.0~
Amazon.com: Logitech M570 Wireless Trackball Mouse – Ergonomic Design with Sculpted Right-Hand Shape, Compatible with Apple Mac / Microsoft, USB Unifying Receiver, Dark Gray (Discontinued by Manufacturer) : Electronics