With the introduction of a SCSI hard disk in my previous computer system, I encountered a major cabling problem. Although the IWill 2935UW card has two internal connectors (1x68 pin UW + 1x50 pin wide) plus a mini 50 pin wide external connector, you can only use two of the three connectors at once.
This wasn't a problem until the new hard disk was fitted, as previously my Minolta 35mm scanner simply plugged into the mini 50 pin on the rear connector.
To overcome this I had to install a much longer 50 pin cable from the controller to the internal CD-Writer and DVD player and continue it to higher up the rear of the case, where an external mini 50 pin to standard 50 pin cable adapter was fitted. This then provided the required connection to the outside for my scanner. To obtain the required length and give some flexibility in connection to the CD and DVD I obtained a long cable with seven connectors at not much more cost than a shorter cable.
Lately I have simplified my system with the introduction of a 120 Gbyte IDE hard disk, so now the SCSI card only serves my CanonScan film scanner.