Can you run a KVM Spotlet on non-J2ME based devices or in regular Web browsers, like an Applet?

No, you must run the Spotlet within the J2ME CLDC environment: Spotlets need libraries included with the CLDC just like Applets need java.applet and the sandbox provided by the Java SDK or Web browser environment.

The only exception I am aware of is that you may be able to run some KVM-enabled apps as applets using the KVM Support classes provided as a part of the PipeDream KVM application. Please refer to the "PipeDream KVM support classes" listing in the J2ME Archive, under:
www.billday.com/j2me/index.html#Tools

Support is not provided for all CLDC API features and functionality. Please refer to the PipeDream entry for more information.

In real devices implementing the CLDC and KVM technologies, you will likely have one or more Profiles that are also implemented on top of the CLDC. Profiles specify the application environment and User Interface (UI) model and components. For instance, the Mobile Information Device Profile (MIDP) specifies how to write "MIDlets", small Java applications that run on CLDC+MIDP (and KVM) mobile devices. Rather than writing your Java app as a Spotlet, you would write it as a MIDlet to run on these devices.

More information on MIDlets is available from the CLDC and MIDP specifications, linked to from the "Specs" section of the J2ME Archive:
www.billday.com/j2me/index.html#Specs