A local architect will be able to design something for you that suits your lot and your family.

Our current home is fully custom. We would prefer not to go that route again and to use a plan with a unique feel, but that has already been used and works well.

Hire an Architect. He will design a home just for you that has a unique feel and works well. An architect can design in many features that have been used before with proven success. Express to him what your specific current concerns are with your fully custom home. Select an architect that has experience designing waterfront homes.

You can talk to builders in other communities where you like the homes. Some of them will build existing plans on your own lot, as well as the communities where you found them.That way you can see the finished homes ahead but also do minimal customizing. usually the smaller local or regional builders do this, as opposed the national names who build only in their own planned communities.

Look at Acorn homes...known for waterfront homes. I have a Deck house (which merged / became Acorn). Modern and very well made.

I'll chime in and add to the litany - hire an architect. It sounds like your last experience with an architect wasn't a complete success. I would search for architects in your state that specialize in your building type - second homes, lake homes, etc.
Stock plans are just that - they are stock. Which means they are designed for no one and everyone. This also means there is going to be something you want to change, which will require redesign fees. By the time you take a stock plan and make the "minor" changes to suite your needs you could have hired an architect and designed everything you really wanted.

Rogue has point and I was not discounting the idea of using an architect from the start. I was merely suggesting another option. I have worked for builders on both ends of the example I gave above. The poster said she wanted an "already used plan". That is what I was going on.
My experience is that a production home is just that, with limited options. But if you found one you liked, and it was a custom or semi custom home builder willing to build on your own lot, and you wanted to tweak options or make some change in the rooms, which I have one for my buyers, then it would be a viable option.

I agree that finding an architect would be the better investment. The shape of your lot will allow for greater creativity when designing your home. Also keep in mind how you spend your time at the lake. Our dock is the most used area, so shade, music, lighting, refrigerator and storage are very important.
I do love to look at stock plans for inspiration. Try this one. http://cdn.houseplans.com/product/8b98fmqkh4v2npcipcombh4g9t/w1024.jpg?v=5

THE DESIGN OF THE HOUSE can be impacted by requirements by the Environmental Protection Agency, the Department of Environmental Protection, and your local Wetland Zoning Ordinances because of being adjacent to water, in addition to other local zoning requirements including size of lot requirements, distance between well and septic if these are not town supplied and property setbacks as well as Association requirements. A good architect that is being paid more than to be a house designer will take these things into account besides your needs, wants, property suitability to design and how the house is situated on the property for maximum appeal when designing a house. If you decide not to use an architect, there are plenty of home designs offered for sale on the internet. If you decide you might want to use an architect, shop around for price, services and compatibility. They are definitely not all equal. Interview them carefully to make sure you are both on board as to what is expected and what is not. And of course read the contract carefully and discuss what you are not comfortable with.