Thanks again for the help, Grégoire Michel! It's good to know that I have another option, even though it's a bit of a round about way. Thank you also for the info on Tout App. I'll have to take a look at that to see if it is going to work with NetSuite.
One way to achieve this with the out of the box Marketo features is to create a Marketo landing page for Internal use only and use that to drive a smart campaign that sends the emails you want.
This would take some bit of work to setup, so if you aren't familiar with creating elaborate smart campaigns, using tokens, and creating and using custom fields you may want to get some outside help.
Also, it is very important you understand the big risk here of someone access this from outside your company. So you need to make sure you take steps to prevent that from happening. For an added bit of reinsurance part of the smart campaign could be "Don't send the email, if not a company email address, and the lead must already exists"
Thanks for the additional suggestion, Raymond Johnson!