The EU has already explored these mythical alternative solutions and there is certainly no technological solution to the backstop. Remaining in the customs union is the only way. The government and gainsayers on both sides have to realise this.
The fault, dear Brutus, is not in our stars but in ourselves.
Of course there's technical solutions, this idea that every lorry must be searched at the border is a myth. The EU and others will claim there is no other solution simply to stop us leaving. They have two choices except the alternative solutions or we leave without a deal